1. Field of the Invention
The present invention relates to an installation for bringing hydrocarbon deposits into production with reinjection of effluents into the deposit or into the well or wells according to the process forming the subject of the parent application and a process for using this installation.
2. Description of the Prior Art
It will be recalled that the working process forming the subject of the parent patent application is intended to maximize recovery of the fluids of liquid hydrocarbon deposits, and to facilitate working thereof, with application, in particular, to heavy and/or viscous hydrocarbon deposits and to hydrocarbon deposits having a high coagulation point.
It will be recalled that this process brings into play recovery of the light condensable and/or gas fractions of the effluent and reinjection thereof into the well or wells and/or the deposit. It comprises heating the effluent coming from the well, separating the gas, liquid and solid phases of the effluent, the compression, cooling and dehydration of the gaseous phase with recovery of the hydrocarbon condensates and reinjection of the liquid phase condensate into the well or into the deposit.
Now, the traditional working of hydrocarbon deposits generally leads to leaving in the deposit a considerable part of the hydrocarbons originally in place for different reasons, some of which are recalled hereafter:
either the crude oil is very viscous and tends to remain entrapped in the matrix in the deposit itself;
or the oil rests on a layer of water which tends to flow more easily than the oil, leading to flooding the production well in a practically irreversible way (water coning);
or the oil underlies an accumulation of gas which will tend to flow more easily than the oil (gas coning), leading to an increase in the production of gas to the detriment of oil production;
or the oil deposit is of small thickness and inserted between a water layer and a gas pocket;
or the pressure of the crude oil in the deposit is too low naturally or because of prior tapping and no longer provides conveyance thereof to the surface, mainly at sea, or if highly deflected production wells are used;
or the crude oil is too viscous and the deposit too deep, to be able to use known production processes and methods;
or the components of the crude oil, coagulate, flocculate or are deposited from the deposit itself as far as the surface installations, because of bringing the deposit into production and thus making working of the deposit very uncertain;
or the surface environment, particularly at sea, and also in regions with a very cold climate does not allow known methods to be used.
For the larger majority of deposits, it is thus necessary to fix a pressure beyond which it is no longer worth while to work the deposit, unless, for some of them, working cannot even be started.
The known processes and techniques relate, on the one hand, to improving the productivity of production wells, mainly by pumping, gas lift and, on the other hand improvement of the displacement of the crude oil in the matrix of the deposit by heating, using water vapor or in situ combustion or by displacement of the crude oil towards the production wells using appropriate fluids injected into specialized wells. These methods, always costly, give sometimes unexpected results and are limited in their applications by factors such as:
the depth of the deposit and its pressure; PA1 the deflection of the wells; PA1 production costs; PA1 possibilities of implementation.
Furthermore, though some are applicable for deposits located on land, they become rapidly unusable at sea when the depth of water is appreciable or when the climatic conditions are harsh.
Finally, in practically all cases, the decision to develop a deposit is founded on the estimate of the recoverable part of the reserves discovered. Should the deposit not behave in the expected way, should it not react well to the treatments which are inflicted on it so as to increase its potential or should the price of crude oil drop, then working of the deposit may lead to the limits of profitability.